This invention relates to an exhaust control valve for an engine and more particularly to an improved engine compression exhaust control valve.
In a wide variety of types of internal combustion engines and, particularly, two-cycle engines, it has been the practice to provide an exhaust control valve for controlling the effective compression ratio of the engine. These exhaust control valves can be utilized for either providing high compression ratios at low and mid range end and reduced compression ratio at the high end so as to improve the overall engine performance throughout the entire speed and low ranges. These exhaust control valves also can be utilized for decompression purposes for assisting in starting.
Generally, the exhaust control valve controls the flow through and auxiliary or supplemental exhaust port of the engine. The type of exhaust control valve normally utilized is a valve that has a cylindrical configuration and, thus, has a relatively large effective surface area that is journaled for rotation in the engine body. These valves, however, are by their very nature disposed so that combustion products may accumulate on them. Therefore, it has been the practice to provide arrangements wherein the valves are cycled either before starting or upon the completion of running so as to remove these deposits from the valve and preclude vane sticking.
Although the self-cleaning operations are helpful, the removed particles tend to accumulate in the exhaust system and may again contaminate the valve when the engine is next run. In addition, in many types of vehicles, the exhaust control valve is operated by a remotely positioned servomotor. The servomotor is coupled to the exhaust control valve through a wire actuator for effecting its operation. As a result, the power available for rotating the valve is relatively small and the valves can easily become stuck.
It is, therefore, a principal object of this invention to provide an improved exhaust control valve for an engine.
It is a further object of this invention to provide an exhaust control valve for an engine that is configured so that, even if combustion particles accumulate on the exhaust valve, they will not interfere with its operation.
It is a further object of this invention to provide an improved exhaust control valve for an engine that has a configuration that minimizes the adverse affects and likelihood of combustion products accumulating on portions of the valve that would interfere with its operation.
It is a further object of this invention to provide an improved exhaust control valve for an engine that can be easily serviced.